JP3903856B2 - Vehicle control device, program - Google Patents

Description

これらのしきい値の大小関係は、以下のようになる。
（ａ）作動指示しきい値／作動解除しきい値の関係

このような関係は、作動指示と作動解除指示のチャタリングが発生しないために必要である。
（ｂ）各減速手段間の作動指示しきい値の関係
０＞Aref11≧Aref41
これは、より発生減速度の小さな手段が先に作動されることが望ましいからである。
（ｃ）各減速手段間の作動解除しきい値の関係
Aref12≧Aref42＞０
これは、発生減速度のより大きな手段が先に解除されることが望ましいからである。
【００９６】
次に、Ｓ３７の警報発生判定では、図１６のフローチャートに示すように、まず、現車速や実加速度等に基づいて警報距離を算出し（Ｓ３７０）、警報要求中であるか否かを判断する（Ｓ３７１）。そして、警報要求中でなければ、レーダセンサ１からのセンサ出力信頼度が予め設定されたしきい値Ｃ９０より大きく、且つＳ３４にて選択された先行車の車両確度が予め設定されたしきい値Ｃ９０より大きいか否かを判断する（Ｓ３７２）。
【００９７】
そして、先行車がないか、センサ出力信頼度≦Ｃ９０、又は、車両確度≦Ｃ９０であれば、警報要求を解除すると共に警報ブザーをオフして（Ｓ３７９）、本処理を終了する。一方、先行車が存在し、センサ出力信頼度＞Ｃ００、且つ、車両確度＞Ｃ９０であれば、車間距離がＳ３７０にて求めた警報距離より小さいか否かを判断する（Ｓ３７３）。そして、車間距離≧警報距離であれば、そのまま本処理を終了し、一方、車間距離＜警報距離であれば警報要求を設定すると共に警報ブザーをオンして（Ｓ３７４）、本処理を終了する。
【００９８】
また、先のＳ３７１にて警報要求中であると判定された場合は、センサ出力信頼度がＣ７０より大きいか否かを判断し（Ｓ３７５）、センサ出力信頼度≦Ｃ７０であれば、そのまま本処理を終了し、一方、センサ出力信頼度＞Ｃ７０であれば、先のＳ３４にて先行車が選択されているか否かを判断する（Ｓ３７６）。そして、先行車が選択されていなければ、Ｓ３７９に移行して警報要求の解除及び警報ブザーのオフ後に本処理を終了し、一方、先行車が選択されていれば、その先行車の車両確度が、予め設定されたしきい値Ｃ７０より大きいか否かを判断する（Ｓ３７７）。
【００９９】
この時、車両確度≦Ｃ７０であれば、そのまま本処理を終了し、一方、車両確度＞Ｃ７０であれば、車間距離がＳ３７０にて求めた警報距離以上であるか否かを判断する（Ｓ３７８）。そして、車間距離＜警報距離であれば、そのまま本処理を終了し、一方、車間距離≦警報距離であれば、Ｓ３７９に移行して警報要求の解除及び警報ブザーのオフ後に本処理を終了する。
【０１００】
次に、Ｓ３８の表示判定では、図１７のフローチャートに示すように、まず、先行車表示中であるか否かを判断し（Ｓ３８０）、先行車表示中でなければ、先行車が有り、且つその先行車の車両確度が予め設定されたしきい値Ｃ９０より大きく、且つセンサ出力信頼度が予め設定されたしきい値Ｃ９０より大きいか否かを判断する（Ｓ３８１）。
【０１０１】
そして、先行車が存在し、センサ出力信頼度＞Ｃ９０、且つ、車両確度＞Ｃ９０であれば、先行車表示をオンにして（Ｓ３８２）、本処理を終了し、一方、先行車が無いか、センサ出力信頼度≦Ｃ９０、又は、車両確度≦Ｃ９０であれば、先行車表示をオフにして（Ｓ３８６）、本処理を終了する。
【０１０２】
また、先のＳ３８０にて先行車表示中であると判定された場合は、センサ出力信頼度がしきい値Ｃ７０より大きいか否かを判断し（Ｓ３８３）、センサ出力信頼度≦Ｃ７０であれば、そのまま本処理を終了し、一方、センサ出力信頼度＞Ｃ７０であれば、Ｓ３４０にて抽出された先行車候補の車両確度がしきい値Ｃ７０より大きいか否かを判断する（Ｓ３８４）。
【０１０３】
そして、車両確度≦Ｃ７０であれば、そのまま本処理を終了し、一方、車両確度＞Ｃ７０であれば、先のＳ３４にて先行車が選択されているか否かを判断する（Ｓ３８５）。そして、先行車が選択されていれば、そのまま本処理を終了し、一方、先行車が選択されていなければ、Ｓ３８６に移行して先行車表示をオフにした後、本処理を終了する。
【０１０４】
以上詳述したように、本実施形態においては、レーダセンサ１が出力する各出力物標についての物標信頼度が反映された車両確度だけでなく、レーダセンサ１のセンサ出力信頼度も用いて、先行車との関係に基づく制御の内容を変更するようにされている。
【０１０５】
従って、周囲の状況がレーダセンサ１でのセンサ出力信頼度を低下させるような状況であっても、適切な車両制御を行うことができ、誤認識された物標に基づいて、過度な制御が実行され、その結果、運転者に違和感を与えたり、不要な緊張を強いてしまうことを確実に防止できる。
【０１０６】
具体的には、ブレーキ要求の判定において、ブレーキ要求中ではない場合、車両確度およびセンサ出力信頼度のいずれか一方でもしきい値Ｃ９０に満たなければ、ブレーキ要求を成立させるか否かの判定（Ｓ３６２３）を行うことなくブレーキ要求を解除し、また、ブレーキ要求中である場合、いずれか一方でもしきい値Ｃ７０に満たなければ、ブレーキ要求を解除するか否かの判定（Ｓ３６２８）を行うことなく、それ以前のブレーキ状態を継続するようにされている。
【０１０７】
つまり、車両確度やセンサ出力信頼度の低い場合は、その物標が誤検出されたものである可能性がある。しかし、本実施形態では、これらの物標に対しては、制御を抑制するようにされているため、誤検出された車両以外の物標に反応して、車両挙動が急変することを防止できる。
【０１０８】
また、同様に、警報発生の判定において、警報要求中ではない場合、車両確度およびセンサ出力信頼度のいずれか一方でもしきい値Ｃ９０に満たなければ、警報ブザーをＯＮするか否かの判定（Ｓ３７３）を行うことなく警報ブザーをオフし、また、警報要求中である場合、いずれか一方でもしきい値Ｃ７０に満たなければ、警報ブザーをＯＦＦするか否かの判定（Ｓ３７８）を行うことなく、それ以前の警報状態を継続するようにされている。このように、本実施形態では、誤検出された可能性のある物標に対する、警報ブザーの無用な吹鳴を防止できる。
【０１０９】
更に、表示判定において、先行車表示中ではない場合、車両確度およびセンサ出力信頼度のいずれか一方でもしきい値Ｃ９０に満たなければ、先行車表示をＯＮにはせず、また、先行車表示中である場合、いずれか一方でもしきい値Ｃ７０に満たなければ、それ以前の警報状態を継続するようにされている。このように、本実施形態では、先行車が存在しないにも関わらず、先行車が存在する旨の表示が行われて運転者に違和感を与えてしまったり、先行車のロストの発生と共に表示内容が頻繁に切り替わる等して、運転者に煩わしさを感じさせてしまうことを防止できる。
【０１１０】
また、本実施形態において、レーダセンサ１では、実測値，予測値，検出履歴を含む７個のパラメータＡ０１〜Ａ０７を用いて個々の認識物標についての物標信頼度Ｓｉを算出しているため、この物標信頼度Ｓｉに基づいて、物標が実際に存在するか否かを精度よく判定することができる。
【０１１１】
また、その物標信頼度Ｓｉを用いて、実際に存在する確率の高い認識物標を抽出し、その抽出した認識物標についてのみ、車両確度や自車線確率を求めるようにされているため、全ての認識物標について車両確度や自車線確率を求める場合と比較して、大幅に演算量を低減することができる。
【０１１２】
更に、レーダセンサ１では、車両周囲の状態の影響を受ける３個のパラメータＴ０１〜Ｔ０３を用いてセンサ出力信頼度Ｔを算出しているため、このセンサ出力信頼度Ｔに基づいて、レーダセンサ１が検知範囲内にある全ての物標を検出しているか否かを精度よく判定することができる。
【０１１３】
なお、本実施形態において、レーダセンサ１が物標認識手段、Ｓ１６０１，Ｓ１６０２が予測手段、Ｓ２０が外挿手段、Ｓ２１４が物標信頼度算出手段、Ｓ２３が認識信頼度算出手段、Ｓ３４が選択手段、Ｓ３５〜Ｓ３８が制御手段、Ｓ３６２２，Ｓ３６２５，Ｓ３６２７，Ｓ３７２，Ｓ３７５，Ｓ３７７，Ｓ３８１，Ｓ３８３，Ｓ３８４が制御変更手段に相当する。また、センサ出力信頼度が認識信頼度に相当する。
【０１１４】
以上、本発明の一実施形態について説明したが、本発明は上記実施形態に限定されるものではなく、例えば以下に示すように、本発明の要旨を逸脱しない範囲において、様々な態様にて実施することが可能である。
（１）上記実施形態では、制御一例として、ブレーキ要求判定、警報発生判定、表示判定を用いたが、先行車との関係に従って実行する制御であれば、どのような制御であってもよい。
【０１１５】
（２）上記実施形態では、車両確度（物標信頼度）とセンサ出力信頼度とは独立に判定を行っているが、センサ出力信頼度に応じて車両確度のしきい値、或いは車両確度自体の値を増減させるように構成してもよい。
（３）上記実施形態では、物標信頼度とは別に、物標信頼度を考慮して車両確度を求めているが、物標信頼度をそのまま車両確度として用いてもよい。
【０１１６】
（４）上記実施形態では、センサ出力信頼度を求めるパラメータとして、停止物の個数を使用しているが、その停止物の位置も考慮して、位置が近いほどセンサ出力信頼度が低くなるように構成してもよい。
【図面の簡単な説明】
【図１】 実施形態のクルーズ制御システムの構成を示すブロック図である。
【図２】 レーダセンサの構成を示すブロック図である。
【図３】 レーダセンサにて実行されるメイン処理の内容を示すフローチャートである。
【図４】 図２のメイン処理中で実行される周波数ピーク抽出処理の内容を示すフローチャートである。
【図５】 図４の周波数ピーク抽出処理中で実行される履歴追尾ピーク抽出処理の内容を示すフローチャートである。
【図６】 図２のメイン処理中で実行される履歴追尾処理の内容を示すフローチャートである。
【図７】 図２のメイン処理中で実行される物標認識処理の内容を示すフローチャートである。
【図８】 図２のメイン処理中で実行される物標外挿処理の内容を示すフローチャートである。
【図９】 図２のメイン処理中で実行される物標選択処理の内容を示すフローチャートである。
【図１０】 図９の物標選択処理中で実行される物標信頼度計算処理の内容を示すフローチャートである。
【図１１】 図２のメイン処理中で実行されるセンサ出力信頼度計算処理の内容を示すフローチャートである。
【図１２】 車間制御ＥＣＵで実行されるメイン処理の内容を示すフローチャートである。
【図１３】 図１２のメイン処理中で実行される先行車選択処理の内容を示すフローチャートである。
【図１４】 図１２のメイン処理中で実行される減速要求判定処理の内容を示すフローチャートである。
【図１５】 図１４の減速要求判定処理中で実行されるブレーキ要求判定処理の内容を示すフローチャートである。
【図１６】 図１２のメイン処理中で実行される警報発生判定処理の内容を示すフローチャートである。
【図１７】 図１２のメイン処理中で実行される表示判定処理の内容を示すフローチャートである。
【符号の説明】
１…レーダセンサ、２…車間制御ＥＣＵ、２ａ…警報ブザー、２ｂ…クルーズコントロールスイッチ、２ｃ…目標車間設定スイッチ、３…ブレーキＥＣＵ、３ａ…ステアリングセンサ、３ｂ…ヨーレートセンサ、３ｃ…Ｍ／Ｃ圧センサ、４…ワイパＥＣＵ、５…エンジンＥＣＵ、５ａ…車速センサ、５ｂ…アクセルペダル開度センサ、６…メータＥＣＵ、６ａ…メータ表示器、１０…発振器、１２，２４…増幅器、１４…分配器、１６…送信アンテナ、２０…受信側アンテナ部、２２…受信スイッチ、２６…ミキサ、２８…フィルタ、３０…Ａ／Ｄ変換器、３２…通信制御部、３４…信号処理部。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle control device that performs control according to the position of a preceding vehicle.
[0002]
[Prior art]
Conventionally, as a technique for improving the driving safety of a vehicle and reducing the burden on the driver, inter-vehicle control is performed to automatically follow the preceding vehicle at a vehicle speed within a predetermined vehicle speed range. Vehicle control devices are known. There are also known a constant speed control for traveling at a constant speed while maintaining a speed set by a vehicle driver within a predetermined vehicle speed range, and a vehicle control device for generating an alarm when the inter-vehicle distance approaches more than necessary. .
[0003]
In these vehicle control devices, a radar sensor is used to detect a target ahead of the vehicle, a preceding vehicle is selected from the detected target, and according to the distance (inter-vehicle distance) and relative speed with the preceding vehicle, Various controls are performed.
In such a vehicle control device (especially when a millimeter wave / microwave radar is used as a radar sensor), the radar sensor detects a target other than the vehicle, such as a roadside object such as a signboard or a minute reflector on the road surface. If there is no possibility of a collision, unnecessary deceleration control is performed, or a warning is suddenly generated at a non-hazardous location, making the user feel uncomfortable or unnecessary. There was a problem of forcing tension
On the other hand, for example, in JP-A-10-129438, JP-A-11-84001, JP-A-2000-38121, etc., a peak frequency detected as a signal component based on a reflected wave from a target is disclosed. Obtain information (distance, relative speed, direction, etc.) on the reception level and target from the components, determine the reliability of the detected target based on the information and its history, and based on the determination result A device for changing control contents (accelerator off, shift down, brake, etc.) is disclosed.
[0004]
[Problems to be solved by the invention]
However, in the above-described apparatus, since it is to determine whether each detected peak is from a target to be detected, it is not possible to determine the peak that has not been detected. There was a problem that the target could not be detected.
[0005]
That is, for example, when there are large roadside objects such as guardrails and soundproof walls, many peak frequency components are buried by reflected waves from these roadside objects, so that it is difficult to detect the target to be detected. In addition, when the overall reception level increases, the signal level of the peak frequency component becomes relatively small, and conversely, the signal level of the noise becomes relatively large, so that noise is likely to be erroneously detected as the peak frequency component. It ends up.
[0006]
Therefore, an object of the present invention is to provide a vehicle control device that can appropriately perform vehicle control based on a detected target regardless of surrounding conditions.
[0007]
[Means for Solving the Problems]
In the vehicle control device according to claim 1, which is an invention for achieving the above object, the target recognizing means recognizes a target reflecting the radar wave based on a detection result obtained by transmitting and receiving the radar wave, and at least The target information including information on the position and speed is obtained, and the preceding vehicle selection means selects the preceding vehicle for the own vehicle from the recognized targets, and based on the target information about the selected preceding vehicle. The control means executes a preset control.
[0008]
Then, the target reliability calculation means obtains a target reliability representing the degree of certainty that the recognized target actually exists for each of the recognized targets recognized by the target recognition means, and recognizes the recognition reliability. The calculation means obtains a recognition reliability indicating the degree of certainty that the target recognition means recognizes all the targets within the detection range, and controls according to the target reliability and the recognition reliability. The changing means changes the control content of the control means.
[0009]
As described above, according to the vehicle control apparatus of the present invention, the control content is not only determined using the target reliability for each target recognized by the target recognition means but also the recognition reliability for the entire target recognition means. Since the change is made, appropriate vehicle control can be performed even if the surrounding situation is a situation where the recognition reliability of the target recognition means is lowered.
[0010]
For example, when the recognition reliability is low, that is, when the probability of erroneously recognizing noise as a target in the target recognition means is high, if the control is changed so that control by the control means is suppressed, Excessive control (for example, acceleration / deceleration control / warning) is executed based on the misrecognized target, and as a result, the vehicle occupant (especially the driver) may feel uncomfortable or force unnecessary tension. Can be prevented.
[0011]
The preceding vehicle selection means may be, for example, the distance from the target recognized by the target recognition means, the own lane probability that is the probability that the target exists on the same lane as the own vehicle, and the target lane. What is necessary is just to comprise so that a preceding vehicle may be selected based on the vehicle accuracy which is the degree which represents the certainty which is a vehicle obtained from recognition time, a shape, etc.
[0012]
Further, the target reliability calculation means, for example, as in claim 2, the larger the received power of the signal component based on the reflected wave from the recognized target, or the smaller the difference from the theoretical value of the received power. As described above, the target reliability of the recognized target may be increased, and the initial detection position at which the recognized target is first detected is the target recognition means as described in claim 3. You may comprise so that the target reliability about the recognition object may become high, so that it is near the peripheral part of this detection range.
[0013]
That is, in the case of claim 2, if the received power is large to some extent, there is a high possibility that it is not noise, and if the distance to the recognition target is known, from the attenuation amount of the radar wave by reciprocating the distance, etc. Since the theoretical value of the received power of the radar wave can be obtained, if the difference between the theoretical value and the actual received power is small, there is a high possibility that it is a target. The standard reliability can be obtained.
[0014]
In the case of claim 3, when the target to be recognized is a vehicle, it cannot be detected suddenly near the center of the detection range, and should be detected at the periphery of the detection range at first. Therefore, the target reliability can be obtained from the initial detection position.
[0015]
By the way, the target recognizing means uses the detection result of the FMCW radar as described in claim 4, and the peak based on the reflected wave from the same target detected in the up-modulation and down-modulation of the radar wave. A configuration may be adopted in which a peak pair that is a combination of frequency components is extracted, and information about a recognized target is obtained based on the peak pair.
[0016]
In this case, since both peak frequency components constituting the peak pair are based on the reflected waves from the same target, naturally the received power of both peak frequency components and the arrival of the reflected waves that generated the peak frequency components are received. The angles representing the directions are almost the same size.
[0017]
Accordingly, the target reliability calculation means, for example, as described in claim 5, the smaller the received power difference between the two peak frequency components constituting the peak pair corresponding to the recognized target, the more the said object about the recognized target. The target reliability may be increased, or the angle difference indicating the arrival direction of the reflected wave is small between the two peak frequency components constituting the peak pair corresponding to the recognized target as described in claim 6. As described above, the target reliability of the recognized target may be increased.
[0018]
Next, in the vehicle control device according to claim 7, the target recognition unit includes a prediction unit that predicts a peak pair to be detected in the current cycle from the detection result in the previous cycle, and according to the prediction in the prediction unit. A target specified from the detected peak pair is set as a recognition target.
[0019]
In this case, the target reliability calculation means is configured to increase the target reliability for the recognized target as the number of times detected according to the prediction by the prediction means is larger, for example, as described in claim 8. Alternatively, as described in claim 9, the smaller the amount of positional deviation between the predicted position of the target based on the peak pair predicted by the predicting means and the detected position of the target based on the actually detected peak pair, The target reliability of the recognized object may be increased.
[0020]
That is, if the target is erroneously detected due to noise or the like, it is unlikely that a peak will be detected as predicted by the prediction means in the next cycle. The target reliability can be obtained based on the deviation from the determined position.
[0021]
Next, in the vehicle control device according to claim 10, the target recognizing unit presets the target reliability among the recognized targets in the previous cycle in which the peak pair corresponding to the prediction by the predicting unit is not detected. For those larger than the threshold value, extrapolation means for extrapolating the peak pair predicted by the prediction means for the recognized object as actually detected is provided.
[0022]
In this case, when the extrapolation is frequently performed on the same recognized target, it can be determined that the possibility that the recognized target actually exists is low.
Accordingly, the target reliability calculation means, for example, as described in claim 11, for the same recognition target, the number of times the peak pair is detected according to the prediction by the prediction means is the number of recognition cycles, and the extrapolation means extrapolates. You may comprise so that the target reliability about the recognition object may become high, so that the frequency | count performed is made into the number of extrapolation cycles, and the ratio of the number of extrapolation cycles with respect to the number of recognition cycles is small.
[0023]
Further, in this case, when the ratio of extrapolated targets is large among all the targets recognized in the same cycle, it can be determined that the target is difficult to recognize.
Therefore, the recognition reliability calculation means, for example, as claimed in claim 12, recognizes the number of recognized targets recognized by the target recognition means as the total number of targets, and the recognized object extrapolated by the extrapolation means. The number of targets may be an extrapolated target number, and the greater the ratio of the extrapolated target number to the total target number, the lower the recognition reliability.
[0024]
In addition, when there are soundproof walls, guardrails, etc. on the roadside, the number of clutter (stopped objects, etc.) detected in addition to the target to be recognized increases, and accordingly, generated based on the detection results in FMCW. The power average value of the frequency spectrum of the beat signal to be increased also increases.
[0025]
Therefore, the recognition reliability calculation means obtains the power average value of the frequency spectrum of the beat signal, for example, as in claim 13, and the recognition reliability increases as the power average value is larger than a preset power threshold value. The degree of recognition may be reduced as the number of clutter specified from the detection result of the target detection means increases. May be.
[0026]
Even if the clutter is detected, if the distance from the host vehicle is long, the influence is small. Therefore, as described in claim 15, the recognition reliability calculation means is identified from the detection result of the target detection means. You may comprise so that recognition reliability may become low, so that the position of the clutter to be done is near to the own vehicle.
[0027]
By the way, specifically, the control means may perform control to increase / decrease the acceleration / deceleration so as to keep the inter-vehicle distance constant as described in claim 16, or the inter-vehicle distance as described in claim 17. When the vehicle approaches more than necessary, a control may be performed to issue an alarm, or the control for notifying the presence of the preceding vehicle when the preceding vehicle exists within a certain distance as in claim 18. May be.
[0028]
Further, the control changing means, specifically, as described in claim 19, when the target reliability and the recognition reliability are lower than a preset threshold, the control itself or the control amount in the control means. In the case where the target reliability and the recognition reliability are lower than a preset threshold as in claim 20, the control state in the previous control means is maintained. Also good.
[0029]
In other words, if acceleration / deceleration control is suppressed or the previous acceleration / deceleration state is continued, when a target other than the vehicle is erroneously detected, the vehicle behavior changes suddenly in response to the erroneously detected target. Can be prevented.
Further, if the inter-vehicle warning is suppressed or the previous inter-vehicle alarm state is continued, it is possible to prevent useless alarm sounding for a falsely detected target.
[0030]
Furthermore, if the control for notifying the presence of the preceding vehicle (for example, “displaying the presence of preceding vehicle” on the display) is suppressed or the previous control state is continued, the preceding vehicle does not exist. If the display indicates that there is a preceding vehicle, the driver may feel uncomfortable, or if the preceding vehicle is lost due to surrounding conditions, the display content will change frequently. It is possible to prevent the user from feeling it.
[0031]
Next, in the vehicle control device according to claim 21, the candidate reliability is set in advance with the target reliability calculated by the reliability calculation unit among the targets recognized by the object recognition unit. A vehicle larger than the threshold is extracted as a preceding vehicle candidate, and the preceding vehicle selection means selects a preceding vehicle from the extracted preceding vehicle candidates.
[0032]
In other words, only the selected vehicle candidate needs to obtain parameters (such as the own lane probability and vehicle accuracy) used when selecting the preceding vehicle, so it is calculated compared to the case of obtaining parameters for all recognized targets. The amount can be reduced.
And each means which comprises the vehicle control apparatus of any one of these Claims 1 thru | or 21 may be comprised as a program for functioning a computer as those means, as described in Claim 22. .
[0033]
In this case, for example, the program is recorded on a computer-readable recording medium provided separately from the computer, and the stored program is loaded into a computer system and started as necessary. Also good. In addition, a program may be recorded in a ROM or backup RAM as a computer-readable recording medium, and the ROM or backup RAM may be incorporated into a computer system. Further, the program is not limited to the program stored in the recording medium, and may be used by being loaded and started via a network.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of a cruise control system to which the present invention is applied centering on an inter-vehicle control electronic control device 2 (hereinafter referred to as “inter-vehicle control ECU”).
[0035]
The inter-vehicle control ECU 2 is an electronic circuit that is configured around a microcomputer, and includes a brake electronic control device (hereinafter referred to as “brake ECU”) 3 and a wiper electronic control device (hereinafter referred to as “wiper ECU”). 4. It is connected to an engine electronic control device (hereinafter referred to as “engine ECU”) 5, a meter electronic control device (hereinafter referred to as “meter ECU”) 6 and the like via a LAN communication bus. Each of these ECUs is mainly configured by a known microcomputer and includes at least a bus controller for performing communication via a LAN communication bus. In this embodiment, data communication between ECUs performed via a LAN communication bus uses a CAN (“Controller Area Network” proposed by Robert Bosch, Germany) protocol generally used in an in-vehicle network. ing.
[0036]
The inter-vehicle control ECU 2 is also connected to a radar sensor 1, an alarm buzzer 2a, a cruise control switch 2b, and a target inter-vehicle setting switch 2c.
Here, the radar sensor 1 is configured as a so-called “millimeter wave radar” of the FMCW system, and transmits / receives a frequency-modulated millimeter wave radar wave to thereby detect a target such as a preceding vehicle or a roadside object. , The preceding vehicle information, which is information about these recognized targets (hereinafter referred to as “recognized targets”), the diagnostic information of the radar sensor 1 itself, and the like are generated and transmitted to the inter-vehicle control ECU 2. The preceding vehicle information includes the own lane representing the probability that the recognized target exists on the estimated traveling path of the host vehicle, in addition to the relative speed with the recognized target, the position of the recognized target (distance data and lateral position data). This includes the probability, the vehicle accuracy representing the degree of certainty that the recognized target is a vehicle, the sensor output reliability T representing the degree of certainty that the radar sensor 1 recognizes the target within the detection range without omission, and the like. ing.
[0037]
The brake ECU 3 detects an M / C pressure in addition to a steering angle and a yaw rate from a steering sensor 3a that detects a steering angle of the vehicle and a yaw rate sensor 3b that detects a yaw rate indicating a vehicle turning state. The brake pedal state determined based on the information from 3c is transmitted to the inter-vehicle control ECU 2 via the LAN communication bus, and the brake hydraulic circuit is provided to control the braking force according to the determined brake pedal state. A brake actuator (not shown) that opens and closes the pressure increase control valve / pressure reduction control valve is controlled.
[0038]
Further, the engine ECU 5 detects the current vehicle speed and the control state (based on detection information from a vehicle speed sensor 5a that detects the vehicle speed, a throttle opening sensor (not shown), and an accelerator pedal opening sensor 5b that detects the accelerator pedal opening). Idle), the accelerator pedal state is transmitted to the inter-vehicle distance control ECU 2. On the other hand, the target acceleration, fuel cut request, diagnosis information, etc. are received from the inter-vehicle control ECU 2, and the throttle opening of the internal combustion engine (in this case, the gasoline engine) is adjusted according to the operating state specified from the received information. A drive command is output to a throttle actuator (not shown) or the like.
[0039]
The wiper ECU 4 performs wiper drive control, and transmits wiper switch information to the inter-vehicle distance control ECU 2. The meter ECU 6 is for displaying various vehicle conditions such as the vehicle speed, engine speed, door open / closed state, transmission shift range, etc. on the meter display 6a.
[0040]
The inter-vehicle control ECU 2 receives the current vehicle speed and control state from the engine ECU 5, and receives control states such as the steering angle (str-eng, S0), yaw rate, and brake control from the brake ECU 3, and the wiper ECU 4 receives the control state. Receives the wiper signal. Based on the preceding vehicle information received from the radar sensor 1, a preceding vehicle to be controlled is determined, and an appropriate inter-vehicle distance from the preceding vehicle is appropriately determined based on detection signals from the cruise control switch 2b and the target inter-vehicle setting switch 2c. As a control command value for adjusting to the engine ECU 5, target acceleration, fuel cut request, diagnosis information, etc. are transmitted to the engine ECU 5, target acceleration, brake request, etc. are transmitted to the brake ECU 3, display data, etc. Send. Further, the inter-vehicle control ECU 2 determines whether or not an alarm has been generated, and if an alarm is necessary, the alarm buzzer 2a is sounded.
[0041]
Here, the cruise control switch 2b includes a cruise set switch, a cancel switch, a set vehicle speed slightly increasing switch, a set vehicle speed slightly decreasing switch, and the like. The cruise set switch is a switch for starting the automatic cruise control, and the cruise control is started by turning on the cruise set switch while the main switch is ON. The cancel switch is a switch for ending cruise control. As will be described later, the cruise control is a concept including both vehicle speed control that travels at a constant speed and inter-vehicle distance control that travels following the preceding vehicle.
[0042]
The set vehicle speed slightly increasing switch is also called an accelerator lever, and is turned on by operating the accelerator lever, so that the stored set vehicle speed is gradually increased. On the other hand, the set vehicle speed slightly decreasing switch is also called a coast lever, and is switched on by operating the coast lever, and gradually reduces the stored set vehicle speed.
[0043]
The target inter-vehicle setting switch 2c is a time required for the host vehicle to travel a distance corresponding to the target inter-vehicle distance between the preceding vehicle and the host vehicle in auto-cruise control (hereinafter referred to as “target inter-vehicle time”). This is a switch for the driver to set. The target inter-vehicle time can be set within a predetermined range.
[0044]
Next, FIG. 2 is a block diagram showing the overall configuration of the radar sensor 1.
As shown in FIG. 2, the radar sensor 1 generates an oscillator 10 that generates a high-frequency signal in the millimeter wave band that is modulated so that the frequency linearly increases and decreases linearly with time, and the oscillator 10 generates the radar sensor 1. An amplifier 12 that amplifies a high-frequency signal, a distributor 14 that distributes the output of the amplifier 12 to a transmission signal Ss and a local signal L, a transmission antenna 16 that radiates a radar wave corresponding to the transmission signal Ss, and a radar wave A receiving-side antenna unit 20 including n receiving antennas for reception.
[0045]
Further, the radar sensor 1 sequentially selects one of the antennas constituting the reception-side antenna unit 20, and receives the reception signal Sr from the selected antenna to the subsequent stage, and is supplied from the reception switch 22. An amplifier 24 that amplifies the reception signal Sr, a mixer 26 that mixes the reception signal Sr and the local signal L amplified by the amplifier 24 to generate a beat signal BT, and an unnecessary signal from the beat signal BT generated by the mixer 26 A filter 28 that removes components, an A / D converter 30 that samples and converts the output of the filter 28 into digital data, and a communication control unit 32 that controls communication with an external device (the inter-vehicle control ECU 2 in this embodiment). , Starting and stopping the oscillator 10, and controlling the sampling of the beat signal BT via the A / D converter 30, and its sampling The signal processing using the processing data, information necessary for the signal processing (vehicle speed, curve curvature radius), and information obtained as a result of the signal processing (preceding vehicle information, diagnostic information, etc.) via the communication control unit 32 And a signal processing unit 34 for performing transmission / reception processing and the like.
[0046]
Among these, each of the antennas constituting the reception side antenna unit 20 is set so that the beam width thereof includes the entire beam width of the transmission antenna 16. Each antenna is assigned to CH1 to CHn.
Further, the signal processing unit 34 is configured around a known microcomputer, and further, an arithmetic processing unit for executing a fast Fourier transform (FFT) process or the like on the data taken in via the A / D converter 30. (For example, DSP).
[0047]
In the radar sensor 1 of this embodiment configured as described above, when the oscillator 10 is started in accordance with a command from the signal processing unit 34, the distributor 14 generates a high-frequency signal generated by the oscillator 10 and amplified by the amplifier 12. By distributing, the transmission signal Ss and the local signal L are generated, and the transmission signal Ss is transmitted as a radar wave through the transmission antenna 16.
[0048]
The radar wave (reflected wave) transmitted from the transmission antenna 16 and reflected back to the target object is received by all the reception antennas constituting the reception-side antenna unit 20, but is selected by the reception switch 22. Only the received signal Sr of the received channel CHi (i = 1 to n) is amplified by the amplifier 24 and then supplied to the mixer 26. Then, the mixer 26 mixes the received signal Sr with the local signal L from the distributor 14 to generate a beat signal BT. The beat signal BT is sampled by the A / D converter 30 after the unnecessary signal components are removed by the filter 28 and taken into the signal processing unit 34.
[0049]
The reception switch 22 is switched so that all the channels CH1 to CHn are selected a predetermined number of times (for example, 512 times) during one modulation period of the radar wave, and the A / D converter 30 is Sampling is performed in synchronization with the switching timing. That is, sampling data is accumulated for each channel CH1 to CHn and for each modulation period of the radar wave during one modulation period of the radar wave.
[Processing by radar sensor]
Here, main processing executed by the signal processing unit 34 of the radar sensor 1 will be described with reference to a flowchart shown in FIG.
[0050]
In this process, first, when information about the current vehicle speed and the curve curvature radius is received from the inter-vehicle control ECU 2 via the communication control unit 32 (S11), the transmission of radar waves is started by activating the VCO 10 (S12). The sampling value of the beat signal BT is taken in via the A / D converter 30 (S13). When the sampling values are taken in as much as necessary, the transmission of the radar wave is stopped by stopping the VCO 10 (S14).
[0051]
Next, frequency analysis processing (in this case, FFT processing) is performed on the acquired sampling values, and each modulation at the time of upstream modulation in which the frequency of the radar wave is increased and downstream modulation at which the frequency is decreased is performed for each channel CH1 to CHn. The power spectrum of the beat signal BT is obtained every time (S15). This power spectrum is hereinafter referred to as a “distance power spectrum” because the frequency corresponds to the distance to the target.
[0052]
Based on the distance power spectrum thus determined, frequency peak extraction (S16), pair creation (S17), history tracking (S18), target recognition (S19), target extrapolation (S20) are performed, and further The target selection based on the results of these processes (S21), the own lane probability for the target selected in the target selection, the vehicle accuracy calculation (S22), and the sensor output reliability calculation (S23), The preceding vehicle information including the speed, position, own lane probability, vehicle accuracy, etc. for the output target obtained by these processes, and the sensor output reliability at the time when the preceding vehicle information is obtained are sent to the inter-vehicle control ECU 2 Transmit (S24) and the process is terminated.
[0053]
Below, the detail of each process shown to S16-S23 is demonstrated in order.
First, in the frequency peak extraction of S16, as shown in the flowchart of FIG. 4, history tracking peak extraction (S160), vehicle traveling direction peak extraction (S162), and normal peak extraction (S164) are performed.
[0054]
Among these, in the history tracking peak extraction of S160, as shown in the flowchart of FIG. 5, the radar sensor 1 first has zero number of recognition targets in the previous measurement cycle (hereinafter referred to as “previous cycle”). (S1600), and if the number of recognized targets is zero, the process is terminated as it is. On the other hand, if the number of recognized targets is not zero, select one of the recognized targets, and based on the information (relative speed, distance, direction) about the selected recognized target, Information (relative speed, distance, direction) to be possessed when detected in the current measurement cycle (hereinafter referred to as “now cycle”) is predicted, and should be detected on the frequency spectrum based on the predicted value. The frequency of the predicted peak is obtained (S1601).
[0055]
Then, information on the frequency of the predicted peak is extracted from each channel, and FFT processing is executed with the extracted information to obtain a power spectrum (hereinafter referred to as “azimuth power spectrum” because the frequency corresponds to the direction) ( In S1602), it is determined whether or not there is a peak on the azimuth power spectrum that matches the predicted value obtained in S1601 (matches within a preset allowable range) (S1603). If such a peak exists, it is determined whether or not the power value of the peak is larger than a preset threshold value PTSD (S1604). If it is larger than the threshold value PTSD, the peak is registered ( S1605).
[0056]
On the other hand, if the peak power value is less than or equal to the threshold value PTSD, the target reliability (calculated in the previous cycle) for the previous recognized target from which the predicted value is calculated is a preset threshold value. It is determined whether or not it is larger than STSD (S1606). If it is larger than the threshold value STSD, an extrapolation permission flag described later is set to 1 (S1607). Is set to 0 (S1608).
[0057]
If it is determined in the previous S1603 that there is no peak that matches the predicted value, or if the peak registration in S1605 or the setting of the extrapolation permission flag in S1607 and S1608 is performed, It is determined whether or not the above-described processing (S1601 to S1608) has been executed for all of the recognition targets (S1609). If there is an unprocessed recognition target that has not been executed, the process returns to S1601 and the unprocessed processing is performed. The same processing is executed for the recognized target. On the other hand, if the processing is completed for all the recognized targets, the present processing is terminated.
[0058]
Next, in the vehicle traveling direction peak extraction of S162, the traveling line of the vehicle is estimated, the power spectrum along the traveling line is obtained, and the peak in the power spectrum has a power value greater than the threshold value PTSD. Only peak registration.
[0059]
Further, in the normal peak extraction of S164, the peak on the averaged distance power spectrum obtained by averaging the distance power spectrum obtained for each channel and each modulation time in S15 at each modulation time in S15. Then, the azimuth power spectrum is obtained for peaks other than those extracted by the history tracking peak extraction, and among the peaks in the azimuth power spectrum, those whose power value is larger than the threshold PTSD are registered as peaks.
[0060]
That is, the peak that exists as predicted from the recognized target recognized in the previous cycle, the peak extracted from the power spectrum on the travel line, and the peak extracted from the averaged distance power spectrum are peaked by the frequency peak extraction (S16). be registered. At the same time, for peaks that do not have sufficient power, an extrapolation permission flag is set for those with a certain degree of certainty that the target reliability, that is, the target, is based on the history so far. It will be.
[0061]
Note that a detection counter and an extrapolation counter are assigned to each pair registered by frequency peak extraction, and the count values CNTi and ICNTi are both set to zero.
Next, in the pair creation in S17, a combination of a peak at the time of uplink modulation and a peak at the time of downlink modulation is set based on the peak registered by frequency peak extraction. Of the set combinations, the power difference between the combined peaks is smaller than the preset power difference threshold PDIF, and the angle difference between the peaks is smaller than the preset angular difference threshold ADIF. Extract only. Further, for each extracted combination, a distance, a lateral position, and a relative speed are calculated, the calculated distance is smaller than a preset upper limit distance DMAX, and the calculated speed is larger than a preset lower limit speed VMIN, and an upper limit is calculated. Only those with a velocity less than VMAX are registered as official pairs.
[0062]
Next, in the history tracking in S18, as shown in the flowchart of FIG. 6, whether or not the number of pairs registered in the pair creation (S17) executed in the previous cycle is zero (S180), It is determined whether or not the number of pairs registered in the pair creation (S17) executed at the current cycle is zero (S181). If either one is zero, this process is terminated.
[0063]
If both the number of pairs in the previous cycle and the number of pairs in the current cycle are not zero, a combination of the pair in the current cycle and the pair in the previous cycle is set (S182), and the combined pair (hereinafter referred to as “combined pair”). 1) is extracted (S183).
[0064]
Then, the predicted position and the predicted speed are calculated based on the information of the pair of the previous cycle among the extracted combination pairs (S184), and the predicted position and the predicted speed, and the detected position and detected from the current cycle pair are detected. Based on the speed, a position difference and a speed difference between the two are obtained (S185), and the position difference is smaller than a preset upper limit position difference DRTSD and whether the speed difference is smaller than a preset upper limit speed difference DVTSD. Is determined (S186).
[0065]
Only when both are small, the detection counter CNTi of the current cycle pair is updated with a value obtained by adding 1 to the detection counter CNTi of the previous cycle pair (S187). Then, it is determined whether or not the above-described processing (S183 to S187) has been executed for all the combination pairs set in the previous S182 (S188). If there is an unprocessed combination pair, the process returns to S183. On the other hand, if the processing has been completed for all the combination pairs, this processing is terminated.
[0066]
That is, for a pair that has a history connection with the pair extracted in the previous cycle, the corresponding previous cycle pair information (detection counter CNTi) is taken over, whereas for a pair that has no history connection, the detection counter is zero. Will remain.
Next, in the target recognition of S19, as shown in the flowchart of FIG. 7, it is determined whether or not the number of the current cycle pair is zero (S190). On the other hand, if the number of cycle pairs is not zero, one of the pairs is extracted (S191), and the detection counter CNTi of the extracted pair is equal to or greater than a preset recognition threshold value CNTTSD. (S192), if it is equal to or greater than the recognition threshold value CNTTSD, the recognition target registration is performed assuming that the pair represents a target (S193).
[0067]
If the detection counter CNTi is smaller than the recognition threshold value CNTTSD, it is determined whether or not the initial detection position has been registered (S194). If it has not been registered, the position obtained based on the pair is initialized. The detection position is registered (S195). Then, it is determined whether or not the above processing (S191 to S195) has been executed for all current cycle pairs (S196). If there is an unprocessed current cycle pair, the process returns to S191 to process all current cycle pairs. If is finished, this process is finished.
[0068]
That is, only those whose history connection equal to or greater than the recognition threshold value CNTTSD is confirmed are registered as recognition targets, and the position obtained from the pair that is the head of the series of history connections is registered as the initial detection position.
Next, in the target extrapolation of S20, as shown in the flowchart of FIG. 8, it is first determined whether or not the number of recognized targets in the previous cycle is zero (S200). This process ends. On the other hand, if the number of recognition targets in the previous cycle is not zero, one of them is extracted (S201), and the extracted recognition target in the previous cycle is the recognition target in the current cycle. It is determined whether or not there is a history connection (S202).
[0069]
If there is a history connection, it is not necessary to perform extrapolation, so the process directly proceeds to S207. On the other hand, if there is no history connection, the extrapolation permission flag for the recognized target in the previous cycle is set to 1. It is determined whether or not (S203). If the extrapolation permission flag is not set to 1, it is not necessary to perform extrapolation, and the process proceeds to S207. On the other hand, if the extrapolation permission flag is set to 1, extrapolation is necessary Then, an extrapolated pair is created based on the predicted value for the recognized target in the previous cycle (S204). The extrapolated pair is made to take over the information (detection counter CNTi, initial detection position) regarding the recognized target in the previous cycle, and is updated by incrementing the extrapolation counter ICNTi (S205), and this extrapolated pair is recognized. The target is registered (S206).
[0070]
Then, it is determined whether or not the above-described processing (S201 to S206) has been executed for all of the recognition targets in the previous cycle (S207), and if there is any unprocessed, the processing returns to S201 and the processing is completed for all. If so, this process ends.
In other words, even if the historical connection of the recognized target is interrupted, the recognition result up to the previous cycle indicates that the probability that it actually exists in this cycle is still recognized by extrapolating the pair. It is supposed to be considered.
[0071]
Next, in the target selection in S21, as shown in the flowchart of FIG. 9, first, it is determined whether or not the number of recognized targets in the current cycle, that is, the number of recognized targets registered in S193 and S206, is zero. Determination is made (S210), and if it is zero, there is no target to be selected, so this processing is terminated as it is.
[0072]
On the other hand, if the number of recognized targets is not zero, one of them is extracted (S212), and target reliability calculation (S214) is performed for the extracted recognized target.
Then, it is determined whether or not the processes of S212 and S214 have been executed for all recognized targets (S216). If there is an unprocessed recognized target, the process returns to S212, while the process for all recognized targets is performed. If the processing has been completed, a predetermined number of recognition targets set in advance are selected as output targets from those having a high calculated target reliability (S218), and this processing ends. Information about each selected output target is output to the inter-vehicle distance control ECU 2 as preceding vehicle information.
[0073]
In the target reliability calculation of S214, as shown in the flowchart of FIG. 10, first, the theoretical power value obtained based on the distance to the recognized target and the power value of the recognized target (up and down modulation). Parameter A01 is obtained by subtracting the detected power value from the theoretical power value based on the detected power value (average power at the time) (S2140), and the power value at the time of each modulation of the recognition target and the power threshold Based on the value PDIF, the parameter A02 is obtained by dividing (normalizing) the difference between the upstream power value and the downstream power value by the power difference threshold value PDIF (S2141), and the angle of each recognition target at the time of each upstream and downstream modulation Based on the value and the angle difference threshold value ADIF, the parameter A03 is obtained by dividing (normalizing) the difference between the up angle value and the down angle value by the angle difference threshold value ADIF (S 142).
[0074]
Further, based on the predicted position and predicted speed obtained from the previous target with history connection, the detected position and detected speed of the recognized target, the upper limit position difference DRTSD, and the upper limit speed difference DVTSD, the predicted position and the detected position The parameter A04 is obtained by dividing (normalizing) the position difference by the upper limit position difference DRTSD, and the parameter A05 is obtained by dividing (normalizing) the speed difference between the predicted speed and the detected speed by the upper limit speed difference DVTSD ( S2143) Based on the extrapolation counter ICNTi and the detection counter CNTi, the parameter A06 is obtained by dividing the extrapolation counter ICNTi by the detection counter CNTi (S2144).
[0075]
Furthermore, it is determined whether or not the initial detection position registered in S195 is the end of the detection range by the radar sensor 1 (S2145). The parameter A07 is set to 0 (S2146), and the parameter A07 is set to 1 assuming that there is a high possibility of noise if it is not an end (S2147).
[0076]
Then, by performing weighted addition using the parameters A01 to A07 and the corresponding weighting coefficients B1 to B7, the target reliability Si of the recognized target is obtained (S2148), and this process is terminated.
That is, here, the smaller the value of the target reliability Si, the higher the probability that the target actually exists.
[0077]
Next, in the own lane probability and vehicle accuracy calculation of S22, for the output target selected by the target selection, the own lane probability indicating the probability that the output target exists in the own lane, and the output target is the vehicle. A vehicle accuracy representing a certainty degree is obtained.
The own lane probability is calculated based on the curve curvature radius (estimated R) of the road input from the inter-vehicle control ECU 2, the distance to the output target, the angle indicating the direction in which the output target exists, and the like. Further, the vehicle accuracy is calculated based on the target reliability obtained in the previous S214, the width of the output target, the speed of the output target, and the like.
[0078]
Next, in the sensor output reliability calculation of S23, as shown in the flowchart of FIG. 11, it is first determined whether or not the number of recognized targets in the current cycle is zero (S230). Since it is not necessary to calculate the output reliability, this processing is terminated as it is.
[0079]
On the other hand, if the number of recognized targets is not zero, the number of extrapolated targets is based on the number of extrapolated targets registered in S206 and the number of all recognized targets registered in S193 and S206. Is divided by the total number of targets to obtain parameter T01 (S231), and among all the recognized targets, the number of targets approaching at the same speed as the own vehicle, that is, the number of stationary objects, is obtained. (S232).
[0080]
Further, the power average value PAVE of the frequency spectrum is obtained (S233), it is determined whether or not the power average value PAVE is larger than a preset power threshold value AVETSD (S234), and if PAVE> AVETSD, the parameter T03 is set to 1 (S236), and if PAVE ≦ ABETSD, the parameter TO3 is set to 0 (S235).
[0081]
Then, by performing weighted addition using the parameters T01 to T03 and the corresponding weighting coefficients K1 to K3, the sensor output reliability T is obtained (S237), and this process ends.
That is, here, the smaller the value of the sensor output reliability T, the higher the probability that the radar sensor detects all the targets existing within the detection range.
[Processing in the inter-vehicle control ECU]
Next, main processing executed by the inter-vehicle control ECU 2 using the radar sensor 1 as described above will be described with reference to a flowchart shown in FIG.
[0082]
In this processing, first, radar data such as preceding vehicle information is received from the radar sensor 1 (S31), and then the current vehicle speed (Vn), engine control state (idle), steering angle from the brake ECU 3, engine ECU 5, and wiper ECU 4 are determined. CAN data such as (str-eng, S0), yaw rate, brake control state, wiper control state is received (S32). At the same time, the set vehicle speed corresponding to the operation state of the set vehicle speed slightly increasing switch and the set vehicle speed slightly decreasing switch of the cruise control switch 2b is obtained (S33).
[0083]
Based on the received data and the set vehicle speed, the preceding vehicle selection (S34), target acceleration calculation (S35), deceleration request determination (S36), alarm generation determination (S37), and display determination (S38) are executed. To do. Details of these processes will be described later. Thereafter, an estimated R (curve radius of curvature) is calculated (S39), and data such as the current vehicle speed (Vn) and estimated R are transmitted to the radar sensor 1 (S40), and the brake ECU 3, the engine ECU 5, and the meter ECU 6 are transmitted. Transmits CAN data such as target acceleration, brake request, fuel cut request, diagnosis and display data (S41).
[0084]
Below, the detail of each process shown to S34-S38 is demonstrated in order.
First, in the preceding vehicle selection in S34, as shown in the flowchart of FIG. 13, first, a preceding vehicle candidate group is extracted from the preceding vehicle information received from the radar sensor 1 in S31 (S340). Specifically, from all the targets included in the preceding vehicle information, the own lane probability is larger than the threshold value P1, and the vehicle accuracy (the target reliability Si is reflected) is larger than the threshold value C50. The vehicle is extracted as a preceding vehicle candidate.
[0085]
Then, it is determined whether or not a preceding vehicle candidate that meets the conditions is actually extracted (S341). If no preceding vehicle candidate is extracted, data when the preceding vehicle is not recognized is set as preceding vehicle data (S344). ), This process is terminated. On the other hand, if a preceding vehicle candidate is extracted, a target with the smallest inter-vehicle distance is selected (S342), and the data of the selected target is set as preceding vehicle data (S343). Exit.
[0086]
In other words, by extracting the nearest target as a preceding vehicle from those with a certain degree of own lane probability and vehicle accuracy, target vehicles other than the own lane and targets other than the vehicle As much as possible to prevent accidental selection.
[0087]
Next, in the target acceleration calculation of S35, it is determined whether or not the preceding vehicle is being recognized. If the preceding vehicle is not being recognized, a preset fixed value is set as the target acceleration.
On the other hand, if the preceding vehicle is being recognized, the target acceleration is obtained using a preset control map using the inter-vehicle deviation ratio and the relative speed with respect to the preceding vehicle as parameters. The inter-vehicle deviation ratio (%) is a value obtained by dividing a value (inter-vehicle deviation) obtained by subtracting the target inter-vehicle distance set by the target inter-vehicle setting SW2c from the current inter-vehicle distance and multiplying by 100. In addition, the relative speed is subjected to low-pass filter processing in order to suppress fluctuations in value due to measurement errors.
[0088]
Next, in the deceleration request determination in S36, as shown in the flowchart of FIG. 14, fuel cut request determination (S360) and brake request determination (S362) are performed in order.
Among these, in the fuel cut request determination, it is determined whether or not a fuel cut request is currently being made. If the fuel cut is not being requested, it is determined whether or not the acceleration deviation is smaller than the reference value Aref11. If the acceleration deviation <Aref11, the fuel cut request is established. On the other hand, if the fuel cut is being requested, it is determined whether or not the acceleration deviation is larger than the reference value Aref12. If the acceleration deviation is greater than Aref12, the fuel cut request is canceled.
[0089]
The acceleration deviation is a value obtained by subtracting the actual acceleration obtained from the current vehicle speed or the like from the target acceleration set in S35.
In the brake request determination in S362, as shown in the flowchart of FIG. 15, it is first determined whether or not the current processing state is a fuel cut request (S3620). The request is canceled (S3629), and this process ends.
[0090]
On the other hand, if the fuel cut is being requested, it is determined whether or not the brake is being requested (S3621). If the brake is not being requested, the sensor output reliability from the radar sensor 1 is greater than the threshold value C90, and It is determined whether or not the vehicle accuracy (target reliability) of the preceding vehicle selected in S34 is greater than threshold value C90 (S3622).
[0091]
If there is no preceding vehicle, or if the sensor output reliability ≦ C90 or the vehicle accuracy ≦ C90, the process proceeds to S3629 and this process is terminated after releasing the brake request. On the other hand, if there is a preceding vehicle, sensor output reliability> C90, and vehicle accuracy> C90, it is determined whether or not the acceleration deviation is smaller than the reference value Aref41 (S3623). If acceleration deviation ≧ Aref41, the process is terminated as it is. On the other hand, if acceleration deviation <Aref41, the brake request is established (S3624), and then the process is terminated.
[0092]
If it is determined in S3621 that the brake is being requested, it is determined whether or not the sensor output reliability is greater than C70 (S3625). On the other hand, if the sensor output reliability> C70, it is determined whether or not the preceding vehicle is selected in the previous S34 (S3626). If the preceding vehicle is not selected, the process proceeds to S3629 and the process is terminated after releasing the brake request. On the other hand, if the preceding vehicle is selected, the vehicle accuracy of the preceding vehicle is set in advance. It is determined whether or not the threshold value is greater than C70 (S3627).
[0093]
At this time, if the vehicle accuracy ≦ C70, the process is terminated as it is. On the other hand, if the vehicle accuracy> C70, it is determined whether or not the acceleration deviation is larger than the reference value Aref42 (S3628). If acceleration deviation ≦ Aref42, the process is terminated as it is. On the other hand, if acceleration deviation> Aref42, the process proceeds to S3629, and the process is terminated after releasing the brake request.
[0094]
The threshold values C90, C70, C50 to be compared with the vehicle accuracy and the sensor output reliability have the following relationship.
C90>C70> C50
Further, the reference values Aref11, Aref12, Aref41, and Aref42 to be compared with the acceleration deviation are as described below.
[0095]

The magnitude relationship between these threshold values is as follows.
(A) Relationship between operation instruction threshold value / operation cancellation threshold value

Such a relationship is necessary so that chattering between the operation instruction and the operation release instruction does not occur.
(B) Relationship between operation instruction threshold values among the respective deceleration means
0> Aref11 ≧ Aref41
This is because it is desirable that the means with smaller generated deceleration is actuated first.
(C) Relationship of operation release threshold value between each deceleration means
Aref12 ≧ Aref42> 0
This is because it is desirable to cancel the means having a larger generated deceleration first.
[0096]
Next, in the alarm generation determination of S37, as shown in the flowchart of FIG. 16, first, an alarm distance is calculated based on the current vehicle speed, actual acceleration, etc. (S370), and it is determined whether an alarm is being requested. (S371). If the alarm is not requested, the sensor output reliability from the radar sensor 1 is greater than the preset threshold value C90, and the vehicle accuracy of the preceding vehicle selected in S34 is set to the preset threshold value. It is determined whether it is larger than C90 (S372).
[0097]
If there is no preceding vehicle, or if the sensor output reliability ≦ C90 or the vehicle accuracy ≦ C90, the alarm request is canceled and the alarm buzzer is turned off (S379), and this process is terminated. On the other hand, if there is a preceding vehicle, sensor output reliability> C00, and vehicle accuracy> C90, it is determined whether the inter-vehicle distance is smaller than the alarm distance obtained in S370 (S373). If the inter-vehicle distance is greater than or equal to the alarm distance, the present process is terminated as is. On the other hand, if the inter-vehicle distance is less than the alarm distance, an alarm request is set and the alarm buzzer is turned on (S374), and the present process is terminated.
[0098]
If it is determined in S371 that an alarm is being requested, it is determined whether the sensor output reliability is greater than C70 (S375). On the other hand, if the sensor output reliability> C70, it is determined whether or not the preceding vehicle is selected in the previous S34 (S376). If the preceding vehicle is not selected, the process proceeds to S379 and the processing is terminated after the alarm request is canceled and the alarm buzzer is turned off. On the other hand, if the preceding vehicle is selected, the vehicle accuracy of the preceding vehicle is determined. Then, it is determined whether or not the threshold value is larger than a preset threshold value C70 (S377).
[0099]
At this time, if the vehicle accuracy ≦ C70, the present processing is terminated as it is. On the other hand, if the vehicle accuracy> C70, it is determined whether the inter-vehicle distance is equal to or greater than the alarm distance obtained in S370 (S378). . If the inter-vehicle distance is less than the alarm distance, the present process is terminated. If the inter-vehicle distance is equal to or less than the alarm distance, the process proceeds to S379, and the present process is terminated after the alarm request is canceled and the alarm buzzer is turned off.
[0100]
Next, in the display determination of S38, as shown in the flowchart of FIG. 17, it is first determined whether or not the preceding vehicle is being displayed (S380). If the preceding vehicle is not being displayed, there is a preceding vehicle, and It is determined whether or not the vehicle accuracy of the preceding vehicle is greater than a preset threshold C90 and the sensor output reliability is greater than a preset threshold C90 (S381).
[0101]
If there is a preceding vehicle, and if the sensor output reliability> C90 and the vehicle accuracy> C90, the preceding vehicle display is turned on (S382), and this process is terminated. If the sensor output reliability ≦ C90 or the vehicle accuracy ≦ C90, the preceding vehicle display is turned off (S386), and this process is terminated.
[0102]
If it is determined in S380 that the preceding vehicle is being displayed, it is determined whether the sensor output reliability is greater than the threshold value C70 (S383). If the sensor output reliability is higher than C70, it is determined whether or not the vehicle accuracy of the preceding vehicle candidate extracted in S340 is larger than the threshold C70 (S384).
[0103]
If the vehicle accuracy ≦ C70, the process is terminated as it is. On the other hand, if the vehicle accuracy> C70, it is determined whether or not a preceding vehicle is selected in the previous S34 (S385). If the preceding vehicle is selected, the present process is terminated as it is. If the preceding vehicle is not selected, the process proceeds to S386 and the preceding vehicle display is turned off, and then the present process is terminated.
[0104]
As described in detail above, in the present embodiment, not only the vehicle accuracy reflecting the target reliability of each output target output by the radar sensor 1 but also the sensor output reliability of the radar sensor 1 is used. The contents of control based on the relationship with the preceding vehicle are changed.
[0105]
Therefore, even if the surrounding situation is a situation where the sensor output reliability of the radar sensor 1 is lowered, appropriate vehicle control can be performed, and excessive control is performed based on the misrecognized target. As a result, it is possible to reliably prevent the driver from feeling uncomfortable or forcing unnecessary tension.
[0106]
Specifically, in the determination of the brake request, when the brake request is not being made, if either the vehicle accuracy or the sensor output reliability does not satisfy the threshold value C90, it is determined whether or not the brake request is satisfied ( The brake request is released without performing S3623, and when the brake request is being made, if either one of the threshold values does not satisfy the threshold C70, it is determined whether or not the brake request is to be released (S3628). Not to continue the previous brake state.
[0107]
That is, when the vehicle accuracy or the sensor output reliability is low, there is a possibility that the target is erroneously detected. However, in this embodiment, since control is suppressed for these targets, it is possible to prevent the vehicle behavior from changing suddenly in response to a target other than the vehicle that is erroneously detected. .
[0108]
Similarly, in the determination of the alarm occurrence, when the alarm is not being requested, if either the vehicle accuracy or the sensor output reliability does not satisfy the threshold value C90, it is determined whether the alarm buzzer is turned on ( The alarm buzzer is turned off without performing S373), and if the alarm is being requested, if either of them does not satisfy the threshold C70, it is determined whether or not the alarm buzzer is turned off (S378). There is no previous alarm state to continue. As described above, in this embodiment, it is possible to prevent an unnecessary sounding of the alarm buzzer with respect to a target that may be erroneously detected.
[0109]
Further, in the display determination, when the preceding vehicle is not being displayed, if either the vehicle accuracy or the sensor output reliability does not satisfy the threshold value C90, the preceding vehicle display is not turned ON, and the preceding vehicle display is not performed. If it is in the middle, if either one does not satisfy the threshold value C70, the previous alarm state is continued. As described above, in the present embodiment, although the preceding vehicle does not exist, a display indicating that the preceding vehicle exists is displayed and the driver feels uncomfortable, or the display contents are displayed together with the occurrence of the lost preceding vehicle. It is possible to prevent the driver from feeling annoyed by switching frequently.
[0110]
In the present embodiment, the radar sensor 1 calculates the target reliability Si for each recognized target using the seven parameters A01 to A07 including the actual measurement value, the predicted value, and the detection history. Based on the target reliability Si, it can be accurately determined whether or not the target actually exists.
[0111]
In addition, because the target reliability Si is used to extract a recognition target with a high probability that actually exists, and only for the extracted recognition target, the vehicle accuracy and the own lane probability are obtained. Compared with the case where the vehicle accuracy and the own lane probability are obtained for all the recognized targets, the amount of calculation can be greatly reduced.
[0112]
Furthermore, since the radar sensor 1 calculates the sensor output reliability T using the three parameters T01 to T03 that are affected by the state of the vehicle, the radar sensor 1 is based on the sensor output reliability T. It is possible to accurately determine whether or not all targets within the detection range have been detected.
[0113]
In this embodiment, the radar sensor 1 is a target recognition means, S1601 and S1602 are prediction means, S20 is extrapolation means, S214 is a target reliability calculation means, S23 is a recognition reliability calculation means, and S34 is a selection means. , S35 to S38 correspond to control means, and S3622, S3625, S3627, S372, S375, S377, S381, S383, and S384 correspond to control change means. Further, the sensor output reliability corresponds to the recognition reliability.
[0114]
Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment. For example, as described below, the present invention can be implemented in various modes without departing from the gist of the present invention. Is possible.
(1) In the above embodiment, brake request determination, alarm generation determination, and display determination are used as an example of control, but any control may be used as long as the control is executed according to the relationship with the preceding vehicle.
[0115]
(2) In the above embodiment, the vehicle accuracy (target reliability) and the sensor output reliability are determined independently, but the threshold value of the vehicle accuracy or the vehicle accuracy itself according to the sensor output reliability. The value may be increased or decreased.
(3) In the above embodiment, the vehicle accuracy is obtained in consideration of the target reliability separately from the target reliability. However, the target reliability may be used as it is as the vehicle accuracy.
[0116]
(4) In the above embodiment, the number of stationary objects is used as a parameter for determining the sensor output reliability. However, considering the position of the stationary object, the closer the position is, the lower the sensor output reliability is. You may comprise.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of a cruise control system according to an embodiment.
FIG. 2 is a block diagram showing a configuration of a radar sensor.
FIG. 3 is a flowchart showing the contents of main processing executed by a radar sensor.
4 is a flowchart showing the contents of a frequency peak extraction process executed in the main process of FIG. 2;
FIG. 5 is a flowchart showing the contents of a history tracking peak extraction process executed during the frequency peak extraction process of FIG. 4;
6 is a flowchart showing the contents of a history tracking process executed in the main process of FIG.
7 is a flowchart showing the contents of a target recognition process executed in the main process of FIG.
FIG. 8 is a flowchart showing the contents of target extrapolation processing executed in the main processing of FIG. 2;
FIG. 9 is a flowchart showing the contents of a target selection process executed in the main process of FIG.
10 is a flowchart showing the contents of a target reliability calculation process executed during the target selection process of FIG.
11 is a flowchart showing the contents of a sensor output reliability calculation process executed in the main process of FIG. 2;
FIG. 12 is a flowchart showing the contents of main processing executed by the inter-vehicle distance control ECU.
13 is a flowchart showing the contents of a preceding vehicle selection process executed in the main process of FIG.
14 is a flowchart showing details of a deceleration request determination process executed during the main process of FIG.
15 is a flowchart showing the content of a brake request determination process executed during the deceleration request determination process of FIG.
16 is a flowchart showing details of an alarm generation determination process executed during the main process of FIG.
FIG. 17 is a flowchart showing the contents of display determination processing executed in the main processing of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Radar sensor, 2 ... Vehicle distance control ECU, 2a ... Alarm buzzer, 2b ... Cruise control switch, 2c ... Target vehicle distance setting switch, 3 ... Brake ECU, 3a ... Steering sensor, 3b ... Yaw rate sensor, 3c ... M / C pressure Sensor, 4 ... Wiper ECU, 5 ... Engine ECU, 5a ... Vehicle speed sensor, 5b ... Accelerator pedal opening sensor, 6 ... Meter ECU, 6a ... Meter display, 10 ... Oscillator, 12, 24 ... Amplifier, 14 ... Distributor , 16 ... transmitting antenna, 20 ... receiving antenna section, 22 ... receiving switch, 26 ... mixer, 28 ... filter, 30 ... A / D converter, 32 ... communication control section, 34 ... signal processing section.

Claims (22)

A target recognition means for recognizing a target reflected from the radar wave based on a detection result obtained by transmission / reception of the radar wave, and for obtaining target information including information on at least position and velocity;
Preceding vehicle selection means for selecting a preceding vehicle for the host vehicle from among the recognized targets that are recognized by the target recognition means;
Control means for executing a preset control based on the target information about the preceding vehicle selected by the preceding vehicle selecting means;
In a vehicle control device comprising:
For each of the recognized targets recognized by the target recognition means, target reliability calculation means for obtaining a target reliability representing the degree of certainty that the recognized target actually exists;
A recognition reliability calculation means for obtaining a recognition reliability representing a degree of certainty that the target recognition means recognizes all targets within the detection range;
Control change means for changing the control content in the control means according to the target reliability and the recognition reliability,
A vehicle control device comprising: The target reliability calculation means is configured to increase the received power of the signal component based on the reflected wave from the recognized target, or as the difference from the theoretical value of the received power is smaller, the target for the recognized target. 2. The vehicle control device according to claim 1, wherein the standard reliability is increased. The target reliability calculation means increases the target reliability of the recognized object as the initial detection position where the recognized target is first detected is closer to the periphery of the detection range of the target recognition means. The vehicle control device according to claim 1 or 2, characterized in that The target recognition means uses the detection result of the FMCW radar to extract a peak pair that is a combination of peak frequency components based on the reflected wave from the same target detected when the radar wave is modulated up and down. 4. The vehicle control device according to claim 1, wherein information relating to the recognized target is obtained based on the peak pair. The target reliability calculation means increases the target reliability of the recognized target as the received power difference between both peak frequency components constituting the peak pair corresponding to the recognized target is smaller. The vehicle control device according to claim 4. The target reliability calculation means calculates the target reliability of the recognized target as the angle difference representing the arrival direction of the reflected wave between the two peak frequency components constituting the peak pair corresponding to the recognized target is smaller. The vehicle control device according to claim 4, wherein the vehicle control device is increased. The target recognizing unit includes a predicting unit that predicts a peak pair to be detected in the current cycle from the detection result in the previous cycle, and the target identified from the peak pair detected according to the prediction in the predicting unit is The vehicle control device according to claim 4, wherein the vehicle control device is a recognized target. The vehicle control according to claim 7, wherein the target reliability calculation unit increases the target reliability for the recognized target as the number of times detected according to the prediction by the prediction unit increases. apparatus. The target reliability calculation unit is configured such that as the amount of displacement between the predicted position of the target based on the peak pair predicted by the prediction unit and the detected position of the target based on the actually detected peak pair is smaller, the recognized object The vehicle control device according to claim 7, wherein the target reliability of the is increased. The target recognition means is a recognition target of the previous cycle in which the peak pair corresponding to the prediction by the prediction means is not detected, and the target reliability is greater than a preset threshold value. 10. The vehicle control apparatus according to claim 7, further comprising extrapolation means for extrapolating a peak pair predicted by the prediction means for the recognized object as actually detected. The target reliability calculation means, for the same recognition target, the number of times the peak pair was detected according to the prediction by the prediction means, the number of recognition cycles, the number of extrapolation means the number of extrapolation cycles The vehicle control device according to claim 10, wherein the target reliability of the recognized object is increased as the ratio of the extrapolation cycle number to the recognition cycle number is smaller. The recognition reliability calculation means includes the number of recognition targets recognized by the target recognition means as the total number of targets and the number of recognition targets extrapolated by the extrapolation means as extrapolation targets. The vehicle control device according to claim 10 or 11, wherein the recognition reliability is lowered as the ratio of the extrapolated target number to the total target number is larger. The recognition reliability calculation means obtains a power average value of a frequency spectrum of a beat signal generated based on a detection result by the FMCW radar, and the power average value is larger than a preset power threshold value. 12. The vehicle control device according to claim 4, wherein the recognition reliability is lowered. The said recognition reliability calculation means makes the said recognition reliability low, so that there are many the number of clutters specified from the detection result in the said target detection means. Vehicle control device. 15. The recognition reliability calculation unit decreases the recognition reliability as the position of a clutter specified from a detection result of the target detection unit is closer to the own vehicle. Any one of the vehicle control apparatuses. The vehicle control device according to any one of claims 1 to 15, wherein the control means performs control to increase / decrease acceleration / deceleration so as to keep the inter-vehicle distance constant. The vehicle control device according to any one of claims 1 to 16, wherein the control means performs a control to issue an alarm when the inter-vehicle distance approaches more than necessary. The vehicle control device according to any one of claims 1 to 17, wherein the control means performs control for notifying the presence of a preceding vehicle when the preceding vehicle exists within a certain distance. The control change unit suppresses the control itself or the control amount in the control unit when the target reliability and the recognition reliability are lower than a preset threshold value. The vehicle control device according to claim 18. The control change means maintains the control state in the control means before that when the target reliability and the recognition reliability are lower than a preset threshold value. The vehicle control device according to claim 19. The vehicle control device according to any one of claims 1 to 20,
Candidate extraction means for extracting, as a preceding vehicle candidate, a target whose reliability calculated by the reliability calculation means is greater than a preset threshold among the targets recognized by the object recognition means; Prepared,
The vehicle control apparatus according to claim 1, wherein the preceding vehicle selecting means selects a preceding vehicle from the preceding vehicle candidates extracted by the candidate extracting means. A program for causing a computer to function as each means constituting the vehicle control device according to any one of claims 1 to 21.

Images